Device and method for detecting a useful signal in a receiver
a receiver and useful signal technology, applied in the field of radio receivers, can solve the problems of not being able to verify the presence of (greatly distorted) useful signals, receivers can still decode very noisy useful signals, and not being able to set the variable-gain amplifier b, etc., to achieve good overall system performance and high noise
Inactive Publication Date: 2009-12-08
INTEL CORP
View PDF7 Cites 7 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Benefits of technology
The invention is a device and method for detecting a useful signal in a signal with low distortion and high noise. The device uses cross correlation to detect the presence of a periodic signal and autocorrelation to estimate the amplitude of the signal. The method involves correlating the signal with a known signal and combining the results. The device and method can be used in wireless local area networks and are particularly useful for detecting the presence of a useful signal in signals with low noise levels. The technical effects of the invention are improved performance of the overall system and reliable and rapid detection of useful signals with minimal implementation expenditure.
Problems solved by technology
Because the amplifier with automatic gain control (AGC) 1 changes the total power, it is not sufficient for detecting the periodic signal u(t) to monitor only the power change of the signal s(t).
Even if the input signal, r(t) as shown in FIG. 2 exhibits a constant mean power, it is not possible to set the variable-gain amplifier 1 immediately to the correct value.
In other words: in the case of a channel with high distortion, the problem is not to verify the presence of the (greatly distorted) useful signal by autocorrelation in the detector but to decode the useful signal in the receiver 4.
This means that the receiver can still decode a very noisy useful signal.
The situation may occur where even though the receiver could decode the almost distortion-free, very noisy useful signal, the detector performing the autocorrelation is not capable of indicating the presence of the useful signal.
The problems in signal detection impair the performance of the system consisting of receiver 4 and detector 3.
The increased error rate disadvantageously results in additional retransmissions.
This lastly results in a reduction in the data throughput for the overall system.
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0048]The description of FIGS. 1 to 7 will not be discussed in further detail in the text which follows, but reference is made to the explanations already made in this respect with regard to the invention.
[0049]If the transmission channel only exhibits low distortion, it is possible to remove the noise from one of the two factors in equation (1). In this case, the received signal is known and it resembles the transmitted signal, compare also FIG. 4. Thus, the useful signal can be detected also by means of the following equation:
[0050]c2(t)=∑titi+Ts(t)(b*(t))(4)
where b(t) is a T-second-long signal component of the known transmitted signal. This signal component could be, for example, the signals or symbols t1 and t2 of the preamble STP or also another signal section of the transmitted signal which is known in the receiver. Furthermore, instead of b(t) in equation (4), a signal derived or transformed from b(t) could also be used, e.g. sgn(b(t)), where sgn(•) is the sign function....
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The device for detecting a useful signal comprises an autocorrelation unit (AK) for autocorrelating a signal (s(t)) which can contain a periodic signal, and a cross correlation unit (CK) for cross correlating the signal s(t) with a known signal (b(t)). Further, the device comprises a logic unit (VE) for logically combining outputs of the autocorrelation unit (AK) and of the cross correlation unit (CK) which outputs a combinatorial signal (d(t)) which specifies whether the useful signal has been detected.
Description
CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a continuation of copending International Application No. PCT / DE03 / 02866 filed Aug. 28, 2003 which designates the United States, and claims priority to German application no. 102 45 039.0 filed Sep. 26, 2002.TECHNICAL FIELD OF THE INVENTION[0002]The present invention generally relates to a device and a method for detecting a useful signal in a receiver, particularly a radio receiver.DESCRIPTION OF RELATED ART AND BACKGROUND OF THE INVENTION[0003]By now, data transmission rates of up to 54 MBit per second are being achieved in wireless local area networks. The specifications for this can be found in “IEEE 802.11a—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHZ band” and in “IEEE 802.11g—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Further Higher Speed Physical Layer Extension in the 2.4 GHz Band...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & AuthorityPatents(United States)
IPC IPC(8): G06F17/15H04L27/06G10L11/02G10L25/90
CPCG10L25/78
InventorMARSILI, STEFANO
OwnerINTEL CORP